Probably the tiniest working 'operating system' available for the TI-89: 2020 bytes, excluding Flib and Flib2. Allows you to run programs (ASM and BASIC), and view expressions, strings, lists, and pictures. A note about the screen shot 'VIEWPIC': It only looks bad because I used Graph-Link to get a shot of a grayscale image, which causes about half the rows to vanish. Now, for the TI-92+!